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By Daniel Fischer Every page present in Europe & the U.S.!
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The latest issue!
| A German companion! (SuW version) Current mission news: MGS (latest pictures!) + Cassini + Galileo + NEAR |
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| (Updated at 21:45 UTC with a new launch date for space shuttle Atlantis) |
Young astronomer dies at the South PoleRodney Marks, 32, an Australian citizen who was conducting astrophysical research at the National Science Foundation's Amundsen-Scott South Pole Station, died at approximately 6 p.m. on Friday, May 12, local time. (U.S. Stations in Antarctica keep New Zealand time.) Marks was spending the austral winter (February through November) at the station. He was employed by the Smithsonian Astrophysical Observatory, working on the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) project. AST/RO is a research project of the University of Chicago's Center for Astrophysical Research in Antarctica (CARA). Marks apparently died of natural causes, but the specific cause of death has yet to be determined. |
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NASA to decide soon on two options for 2003 Mars missionIn 2003, NASA may launch either a Mars scientific orbiter mission or a large scientific rover which will land using an airbag cocoon, like that used on the successful 1997 Mars Pathfinder mission - or not launch anything. The two concepts were selected from dozens of options that had been under study, and NASA will make a decision in early July, which could also be not to launch at all. Two teams, one centered at the JPL and the other at Lockheed Martin Astronautics, will conduct separate, intensive two-month studies to further define the concepts. If one of the missions is selected, the cost will be about the same as the successful 1997 Mars Pathfinder mission (adjusted for inflation)."Our budget will support only one of these two outstanding missions for the 2003 launch opportunity, and it will be a very tough decision to make," said NASA Associate Administrator for Space Science Ed Weiler: "Following this decision, later in the year we will have a more complete overall Mars exploration program to present to the American public." Adds NASA Mars Program Director Scott Hubbard: "These two mission concepts embody the requirements we have learned through the hard lessons of two recent Mars mission failures, and either one will extend the tremendous scientific successes we have had with the Mars Global Surveyor and Mars Pathfinder." The Mars Surveyor Orbiter would be a multi-instrument spacecraft, similar in size to the currently operating Mars Global Surveyor and designed to recapture all the lost science capability of the Mars Climate Orbiter mission as well as to seek new evidence of water-related materials. Telecommunications relay equipment that could be used to support Mars missions for 10 years also would be included. The Mars Mobile Lander would be based on the Athena rover, which already has been operated in field tests and was considered once for the canceled 2001 lander. The concept being proposed for the 2003 mission involves packaging the 130-kilogram rover in a system similar to the 1997 Mars Pathfinder structure, cushioned on landing by airbags. Unlike the 1997 mission, however, the four-petal, self-righting enclosure would serve only as a means to deliver the rover to the surface and not function as a science or support station. |
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Another cosmology balloon confirms BOOMERANG, raises new questionsObservational cosmology is progressing at a quickening pace: Only weeks after the publication of the highest-resolution map of the Cosmic Microwave Background by the BOOMERANG balloon (see Update # 187 story 3), an even sharper images has become available, although of an even smaller piece of the sky. This time a detector had flown only a few hours, but the Millimeter Anisotropy eXperiment IMaging Array or MAXIMA had no trouble seeing the structure in the CMB down to a size scale of 10 arc minutes.And again it's not the picture that raises eyebrows but its mathematical analysis: As with BOOMERANG (some team members are identical, but the data analysis was completely independent) there is a strong 'signal' at around one degree of arc, confirming the result from BOOMERANG and earlier CMB experiments that the geometry of the Universe is flat. But even more interesting is what MAXIMA did not see at even smaller scales: There should have been a marked second peak in the angular power spectrum, but it turns out to be pretty weak. This finding - also evident in the BOOMERANG data - requires some modification of the favorite view of the Universe: For example, the Big Bang could have produced more baryons than thought (and people thought they had found most of them: see last Update story 3), or some other aspect of the current Big Bang model has to be modified. Which one has become a topic of heated debate among cosmologists ever since the BOOMERANG data were published (see the sidebar for some opinions), but fortunately the next generation of CMB telescopes should provide an answer: The ratio of the 2nd to an - as yet unobserved - 3rd peak is very sensitive to these details! |
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Fighting over the Hubble Constant at a new levelOne year after the long-awaited presentation of the "final" value of the Hubble Constant (Ho) by the Ho Key Project (H0KP) team (see Update # 132) the result is being attacked from two completely different angles - and if either one of the doubts or both turn out to be justified, the value of Ho could jump from the 71+/- 6 km/s/Mpc the H0KP announced to anywhere between 80 and almost 100! Which could once more raise the trouble that the Universe would seem younger than some stars in it, even with the modern cosmological view of a low-density cosmos with a cosmological constant.The first problem raised had been the distance of the Large Magellanic Cloud on which the cosmological distance ladder rests: Several lines of evidence for a smaller distance than the H0KP had used were soon published (see Updates # 133 story 2, 148 story 4 and 168), and incorporating the new LMC distance would increase the Key Project value by 10 or more percent. And now a new, even more fundamental problem has turned up that calls the whole approach of the H0KP into question - and again raises the possibility that Ho is way greater than 71, more like 85 to 90, even with the "old" LMC distance. To determine the Hubble Constant you cannot simply measure the distance to a sample of moderately distant galaxies where the Hubble Space Telescope can still see Cepheid variable stars: Those galaxies are not in the true 'Hubble flow' of cosmic expansion, but their velocities are strongly influenced by other masses in space. The traditional way out is to calibrate secondary distance indicators with the help of those galaxies and to observe the same indicators in much more distant galaxies that track the cosmic expansion: The H0KP had used four different secondary indicators and combined the results. But there is another approach: Stick to the galaxies where you can measure the Cepheid light curves and be sure (modulo the LMC distance) about their distances - and determine the "errors" of their velocities due to other masses. This has now been done, using two different techniques, one relying on a big catalog of galaxies and their distribution in the Universe based on detections by the IRAS satellite, and another one where the local velocity field is dominated by a few simple components (such as the famous 'Great Attractor'). Such corrections introduce new uncertainties, of course, but so do the secondary distance indicators that are not needed now. For the new analysis the Cepheid Period/Luminosity relationship was determined anew, with the help of some 700 of these stars found in the LMC (the H0KP will adopt those stars in the future, too) - which alone raised Ho to 75. But the velocity corrections gave Ho an even bigger boost, to at least 85 and possibly over 90. And this is still with the "old" LMC distance - throwing in the new values would push Ho to around 95! And even 90 would raise the problem of an Universe too young to explain the oldest stars. Still the values for the density of the cosmos and the star ages are a bit uncertain and everything could be forced to just fit - but with ever more precise values there could be a new "crisis in cosmology" on the horizon ...
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100 000 redshifts measured in big sky surveyThe 2dF Galaxy Redshift Survey has now reached a major landmark: The distance to the 100 000th galaxy in the Survey has been measured, making their map four times larger than any previous survey. The large international collaboration involves more than 30 scientists from 11 institutions. One of the main aims of the survey is to learn more about the three-dimensional structure of the Universe: To construct a three-dimensional map of the Universe requires measurements of the distances to a very large number of galaxies, using Australia's largest optical telescope, the 3.9 meter Anglo-Australian Telescope and a remarkable instrument called 2dF. In order to make the information more easily accessible to the public, the Swinburne Centre for Astrophysics and Supercomputing has now produced an exciting new computer visualisation: "Fly-through of the 2dF Galaxy Redshift Survey." |
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Cosmic gamma-ray background explained?Most of the gamma radiation reaching the earth from all directions may actually be leftover energy from massive shock waves induced by gravitational forces, a new model for the cosmic gamma-ray background says: Operating on intergalactic clouds of gas, these forces caused them to collapse into themselves, creating giant galactic clusters. This process produced electrons moving at nearly the speed of light, which then collided with the low energy photons of the cosmic microwave background radiation - the collision scattered the photons and increased the energy of a fraction of them to that of gamma rays, thus producing the gamma-ray background radiation seen in today's universe. |
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Constant speed of light remeasured with Gamma BurstsThe speed of light is independent of the speed of the light source to within one part in 10^20: Kenneth Brecher of Boston University has reached this conclusion by studying gamma radiation arriving from distant Gamma Ray bursters (GRBs). Radiation will come to us from the near side of a presumed expanding object, and from the receding far side, and because of the explosive nature of the GRB engine (as mysterious as it is), its near and far sides might, at least in some cases, be moving apart at a fair fraction of the speed of light. Any differential in the speed of light arising from these two gamma-emitting locations would then result (after a very long extragalactic journey) in a stretched-out gamma pulse upon arriving at Earth.In addition, the emitted gamma rays would scatter off of energetic thermal electrons on leaving the burst sources, further broadening the pulses. From the observed sharpness of the arriving pulses, one can deduce the independence of c from the source speed to be less than a part in 10^20, an improvement by a factor of 100 billion, says Brecher, over previous tests of this tenet of relativity theory. At an APS meeting in Long Beach, CA, Brecher argued that the speed of light is even more fundamental a concept than light itself since it is related to the intimate relation between space and time. Therefore he urged that c be referred to as "Einstein's constant," in analogy to Planck's constant, which sets the scale of quantum measurements. |
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Albert is back: last long-lost asteroid recovered!Nearly 89 years after its original discovery, the long-lost asteroid (719) Albert has finally been reobserved! With this finding, it can finally be said that the current position is known of every one of the 14 788 asteroids in the numbered sequence that began with the discovery of (1) Ceres in 1801. No longer is there this short yet embarassing list of objects that had been given numbers prematurely and which were later lost due to a poorly known orbit. Albert's orbital period is actually 4.28 years, not 4.1 as was believed when it was discovered in 1911. This is now known because, earlier this month, Albert was, at last, again under observation. It was identified by the International Astronomical Union's Minor Planet Center (MPC), which was analyzing recent data from the Spacewatch asteroid survey project, observing with a 36-inch telescope on Kitt Peak.This project is one of four or five around the world that regularly scan the sky electronically for asteroids that can come close to the Earth, often nowadays much closer than is possible for Albert. Gareth V. Williams, the Associate Director of the MPC, has been vigilant in checking the frequent new discoveries of Earth-approaching asteroids by all the survey groups for the purpose of seeing if they link with asteroids discovered earlier. Williams had dreamt about finding the lost asteroid (719) Albert since he was still in school in England. When he had joined the MPC staff in 1990, all but two of the lost numbered asteroids had been found. A year or so later, Williams was able to identify (878) Mildred in recent images. Down to only one lost numbered asteroid, Williams had since checked every asteroid reported to the MPC in hopes of spotting the long-lost Albert. |
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Leaving the solar system with a solar sailNASA's Marshall Space Flight Center in Huntsville, Ala., is developing space sails technology that could one day power a mission beyond our solar system: Such an interstellar probe would travel over 37 billion kilometers or 250 Astronomical Units beyond the edge of the solar system in about 15 years. Proposed for launch in a 2010 time frame, the interstellar probe - or precursor mission, as it's often called - will be powered by the fastest spacecraft ever flown. Zooming toward the stars at 93 km/s, it would cover the distance from New York to Los Angeles in less than a minute, more than 10 times faster than the Space Shuttle's on-orbit speed of 8 km/s. Researchers are optimistic about recent breakthroughs with strong, lightweight composite materials: A leading candidate for sails is a carbon fiber material that would unfurl like a fan when it's deployed from an expendable rocket. |
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Spacewalking cosmonauts see traces of fire outside MirEvidence of an electrical short-circuit that charred external wires on the Mir space station has been found by the two cosmonauts during their May 12 EVA - the cosmonauts also brought inside the station a panel which tested a new glue for sealing air leaks onboard spacecraft and an experimental solar array, which had been exposed to the environment of space: Space.com, BBC, SpaceRef, SPIEGEL, AFP, RP, AP, SpaceViews; MirCorp Press Release.What was planned during the EVA: Space.com. How life on Mir is like, as reported by U.S. guest Linenger. The countdown for STS-101has resumed on May 15th, for a 10:12 UTC launch on May 19th - there are no major problems being addressed by NASA and forecasters are predicting a 90 percent chance of good weather on the 19th and 20th, with no problems in sight at the TAL sites either, but a delayed Atlas launch has forced Atlantis' back one day: Status, stories from May 16 (AP, Space.com, BBC), 15 ( Space.com, Fla. Today, SpaceViews, Discovery) and 11.Russian Rockot booster in business!The first demonstration flight of a Rockot booster went off without a hitch in northern Russia on May 16th, putting the new commercial launcher (a Russian-German joint venture) officially in business - the light-weight booster is based on a UR-100NU ICBM, also known as SS 19 'Stiletto': Homepage, details, SpaceViews, Space.com.The Titan 4 returns to servicewith the launch of a $250 million DSP satellite on May 8th - the Air Force and contractors Lockheed Martin and Boeing had been harshly criticized by Congress after $3 billion in rocket losses: AP, SpaceViews, Spaceflight Now, Fla. Today.Remains of rockets are raining from space, hitting Earth with disturbing frequency - and it is now certain that every Delta rocket launched sends certain pieces back to the ground: Space.com. Investors for Iridium? "There are some qualified investors who are in [a] dialog with the banks": Space.com.
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A galaxy in front of another onehas been imaged by Hubble - this way the dust in the foreground object is highlighted as never before: STScI Press Release, Space.com, CNN, BBC.HESSI damage explainedThe High Energy Solar Spectroscopic Imager (HESSI) spacecraft was damaged March 21 during pre-flight vibration tests because of a malfunction in the vibration test system at NASA's JPL (see Update # 183 small items) - the reason was a misalignment between two pieces of the test stand that led to an abnormally high level of static friction. The computer used to control the test then tried to compensate and induced too large a shock into the satellite: NASA Press Release (Spacefl. Now version), Space.com, SpaceViews, AP stories.U.S., S.U. planned to nuke the Moonas early demonstrations of power at the beginning of the space race - while the Soviet idea had been known for years, it has now become clear that the U.S. had similar 'visions': Space.com, NYT, Discovery, AP. The Soviet plans: a Russian article and a SpaceViews story.Burial on the Moon to be offered by Celestis - when the Earth orbit isn't good enough for your ashes: AP, BBC, Space.com. No plans for a U.S. return to the Moon are in the works, despite dramatic headlines: SpaceViews, referring to this Space.com article. How the Earth generates its B fieldhas finally been simulated successfully in several labs, where a magnetic field has been created the same way the Earth does: a paper and Phys. Rev. Focus.
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